MARKET WATCH Ferrari Dino 246GTIt’s increasingly clear that when you make decisions about deviating from the factory spec of your car during restoration, you need to have your priorities straight. If your only concern is that the car looks and drives exactly as you like, then build it to whatever spec and colour scheme pleases you and ignore the self-appointed originality police. Just be prepared to sell for less than the market maximum when the time comes.

Time was when if you upgraded a classic to more desirable spec, or to a more fetching colour scheme, as long as the changes were all factory options, or if they simply made the car better to drive, they wouldn’t harm its value at all. Sometimes they added to its saleability. But the sale of two Ferrari Dino 246 GTs at the Bonhams Festival of Speed sale was more evidence that buyers are putting ever greater emphasis on originality, with the more correct car selling for a 47 per cent premium over one with a colour change and some detail shortcomings. Of course there are exceptions – some marque specialists have made such a reputation for their own packages of upgrades that they’ve created a brand, one that carries its own premium.

MARKET WATCH Honda NSXOnce upon a time, NSX values started to move; now Honda’s user-friendly supercar has stalled. Bad luck if you bought one as an investment then, but a great opportunity if you fancy the idea of a beautifully honed and thrilling driving machine without all of the usual supercar baggage – show off styling, tetchy temperament and lose-your-shirt maintenance bills.

Neither of the last two examples to come up for auction made enough of a dent on their £30k-35k estimates to tip over the reserves, and those in the classifieds seem in no rush to sell. Time to get out there and make some cheeky offers.

MARKET WATCH Top 10 growers of the monthThere’s a lot of talk this year about the classic car market cooling off, particularly the high-value auction darlings typified by Mercedes 300 SL Gullwings and Roadsters, chrome-bumper Ferraris and pre-impact bumper Porsche 911s. You can look for deeper meaning to this, but the most rational explanations seem to be over-supply from vendors trying to cash in on a boom, and buyer disillusionment with the belief that values will values will continue to soar at the same rate.

But this cooler mindset doesn’t apply evenly throughout the classic car market, as evidenced by the Market Movers data in the latest issue of Classic Cars magazine. The top ten climbers have all grown by at least 23 per cent since the last update, with some surprising top performers like the Austin Atlantic and Ford Corsair GT each jumping more than 40 per cent and even numerous classics like MG Midget MkII and MkIII climbing 33 per cent. Porsche 968 Club Sports and BMW 3.0 CSLs have both shown another recent spurt, at 38 and 33 per cent respectively, so it’s hard to generalise where the recent growth has concentrated, and ever more challenging to predict where it will strike next.

MARKET WATCH Mercedes SLKClassic car magazines can be guilty of unrealistically low ‘Prices from £Xk’ headlines in the hope of snaring new readers, but at Classic Cars magazine we focus on what you’d really pay for a car in a condition that you’d actually want to own. So when the latest issue says that a Mercedes 230 SLK can be yours from £2.5k, we’re talking about a good example with 60-70k miles and full service history.

Incredible value for such a refined and once expensive roadster, and one with the party trick of a push-button, folding electric hardtop. Even the 320 V6 isn’t much more than twice that for a similarly well-looked after example. All you have to do is navigate your way around the poorly maintained examples that have been glossed up for a quick profit, so it’s worth checking out the buying guide in the latest issue of Classic Cars magazine which details the most serious and expensive faults, and shows you how to spot them. After that all you need to do is seize the best bits of our sporadic summer, yours at the push of a button.